Update axum requirement from 0.7 to 0.8

Updates the requirements on [axum](https://github.com/tokio-rs/axum) to permit the latest version.
- [Release notes](https://github.com/tokio-rs/axum/releases)
- [Changelog](https://github.com/tokio-rs/axum/blob/main/CHANGELOG.md)
- [Commits](https://github.com/tokio-rs/axum/commits)

---
updated-dependencies:
- dependency-name: axum
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Cargo.toml

@@ -52,7 +52,7 @@ tokio.workspace = true
 
 [dev-dependencies]
 tikv-jemallocator = "0.6"
-axum = "0.7"
+axum = "0.8"
 # re-import tokio to enable all its features. This is required to
 # successfully compile the test snipptes that are part of the documentation
 tokio = { version = "1", features = ["full"] }

example/Cargo.toml

@@ -7,6 +7,6 @@ publish = false
 [dependencies]
 jemalloc_pprof = { path = ".." }
 tokio = { version = "1", features = ["full"] }
-axum = "0.7.2"
+axum = "0.8.1"
 [target.'cfg(not(target_env = "msvc"))'.dependencies]
 tikv-jemallocator = { version = "0.6", features = ["profiling", "stats", "unprefixed_malloc_on_supported_platforms", "background_threads"] }